Radiocarbon of dissolved humic substances in river waters from the Chernobyl area

Abstract

Radiocarbon (14C) was used to study the origin and transport of aquatic humic substances in river waters at the Chernobyl area, which received a pulse input of 14C as a consequence of the nuclear accident. Water samples were collected in April 1999 from the Pripyat and Sakhan Rivers, which flow through the radioactive contaminated area (30 km exclusion zone). The Δ14C values of humic and fulvic acids ranged from −68‰ to +75‰ and were ∼400‰ lower than those of non-contaminated environments. The aquatic humic substances may be derived mainly from those of bog, peat, and podzolic soil with older 14C age, and thereby reflect a larger proportion of older groundwater humic substances. Contribution of 14C by the Chernobyl accident appears to be small because of the long residence time of organic carbon at the surface soil.